I wouldn't say the democrats have refined their messaging. The leftist democrats who are saying these things are still a minority while the majority of the democratic party want to be seen as centrists who aren't hostile to big business.

But at least it has gone from 1 prominent person saying these things (Sanders) to now enough that you can no longer count them on just one hand.

The money, power and majority of the democratic party is still against them. But, it really seems like voters are behind them.

Perhaps the good thing is that so many democratic politicians lack a spine. It means that if it's clear that the democratic socialist message has momentum, they'll happily pivot to the new shiny thing and adopt it as if it's where they were all along.